Resource sharing optimality in WiFi infrastructure networks

In WiFi networks, mobile nodes compete for accessing a shared channel by means of a random access protocol called Distributed Coordination Function (DCF). Although this protocol is in principle fair, since all the stations have the same probability to transmit on the channel, it has been shown that unfair behaviors may emerge in actual networking scenarios. Assuming that a contending node can dynamically change its strategy, by tuning its contention parameters to nonstandard values on the basis of channel observations, we prove that, for infrastructure networks with bidirectional traffic and homogeneous application requirements, selfish access strategies are able to reach equilibrium conditions, which are in many cases also Pareto optimal. Indeed, the station strategies converge toward values which maximize a per-node utility function, while maintaining performance fairness.